The city of Denver now estimates that the start of its Colorado Convention Center expansion will be delayed by at least a year and possibly longer, following an alleged bid-rigging scandal that derailed contractor selection late last year.

City officials say the revised completion date for the $233-million project is 2023, although they insist that’s only a “placeholder” date until a contractor is hired. The city has also extended an $8-million contract to development consultant Rider Levett Bucknall as the new owner’s representative, according to documents released last month. That’s $1 million less than the previous contract with Trammell Crow. That firm was fired for allegedly sharing project information with Mortenson, one of the contractors vying for the job. The project will add a rooftop patio and expand exhibit and ballroom space to allow for larger conventions.